M.C.Q : Electrostatics ( 1 to 10)

LEVEL – I

1. An electron of mass me , initially at rest, moves through a certain distance in a uniform electric field in time t1. A proton of mass mp , also initially at rest, takes time t2 to move through an equal distance in this uniform electric field. Neglecting the effect of gravity, the ratio t2 / t1 is equal to

(A) 1

(B)

(C)

(D)

2. If positively charged pendulum is oscillating in a uniform electric field as shown in figure. Its time period as compared to that when it was uncharged:

(A) will increase

(B) will decrease

(C) will not change

(D) will first increase then decrease

3. A and B are two concentric spheres If A is given a charge Q while B is earthed as shown in figure :

(A) The charge density of A and B are same

(B) The field inside and outside A is zero

(C) The field between A and B is not zero

(D) The field inside and outside B is zero

4. The maximum electric field intensity on the axis of a uniformly charged ring of charge q and radius R will be

(A)

(B)

(C)

(D)

5. The figure is a plot of lines of force due to two charges q1 and q2.

Find out the sign of charges

(A) both negative

(B) Upper positive and lower negative

(C) both positive

(D) upper negative and lower positive

6. There are two concentric metal shells of radii r1 and r2(>r1). If the outer shell has a charge q and the inner shell is grounded, the charge on the inner shell is

(A) zero

(B) -(r1/r2)q

(C) r1r2q

(D) ∞

7. Electric charge q , q and -2q are placed at the corners of an equilateral triangle ABC of side L. The magnitude of electric dipole moment of the system is

(A) qL

(B) 2qL

(C) (√3)qL

(D) 4qL

8. Three identical particles of charge Q and mass m are placed such that they form an equilateral triangle of side l . If they are released simultaneously. The maximum speed attained by any one of the particles will be

(A)

(B)

(C) Zero.

(D) none of these.

9. A point charge q is placed at a point on the axis of a non-conducting circular plate of radius r at a distance R ( >> r) from its center. The electric flux associated with the plate is

(A)

(B)

(C)

(D)

10. In the electric field due to a point charge q, a test charge is carried from A to the points B, C, D and E lying on the same circle around q. The work done is